Log a message and return when a click in a splitview was not on a divider. Not...

Log a message and return when a click in a splitview was not on a divider. Not sure why it would happen but there was an assertion in the field.

PTYSplitView.m

@@ -75,7 +75,11 @@
     [[self delegate] splitView:self draggingWillBeginOfSplit:clickedOnSplitterIndex];
     // mouseDown blocks and lets the user drag things around.
-    assert(clickedOnSplitterIndex >= 0);
+    if (clickedOnSplitterIndex < 0) {
+        // You don't seem to have clicked on a splitter.
+		NSLog(@"Click in PTYSplitView was not on splitter");
+        return;
+    }
     [super mouseDown:theEvent];
     // See how much the view after the splitter moved